Glad you were able to rescue yourself. I run two small forums, one on 20G storage and the other on 25G. I do have to use quite a lot of time and ingenuity sometimes to keep that working. But also I seem to keep using (and posting about) the same set of tactics. See below.
Discourse development optimises for other things than running on minimal-cost hardware - although it just about manages to continue to work for me in my constrained environment. Long may it continue.
The key to working in small-storage setups is to measure what’s going on - too often I see people guessing at what might be going on. My approach will always start with
For more, perhaps search my posts for prune and journalctl and kernel.